1. Field of the Invention
The present invention relates to cooling systems, and particularly radiators for vehicle cooling systems.
2. Description of the Related Art
Vehicle engine coolant radiators conventionally are positioned across the front of a vehicle, parallel to the vehicle front, which forces air through the radiator due to motion of the vehicle in the forward direction. In addition, a radiator fan normally is provided behind the radiator to draw even greater quantities of air through the radiator.
Many variations on this positioning are known. For example, U.S. Pat. No. 3,715,001 (Wilson) teaches a flat radiator which is angled relative to the vertical axis. The top and bottom sides of the radiator are sealed against the walls of a chamber, and fans are provided on each side of the radiator. This structure allows air to flow in from the top and out the side of the radiator, or vice versa, and avoids the need for air to pass beyond the chamber behind the radiator. However, all air flowing through the system must flow through the radiator.
U.S. Pat. No. 3,995,603 (Thien et al.) teaches positioning two flat radiators at an angle relative to one another about the central axis at the front of an engine. The closer edges of the two radiators are sealed by a housing, while the outer edges are sealed to a shroud surrounding an axial flow fan in front of the radiator. Again, all air must pass through the radiator.
U.S. Pat. No. 4,076,072 (Bentz) teaches a radiator structure having a plurality of angled core elements arranged in a zigzag pattern with the apices of the zigzag extending to the front and back of the vehicle. An axial flow fan is provided behind this zigzag radiator structure.
In some applications, e.g., agricultural and industrial equipment, large volumes of debris are found in the air as it approaches the radiator. With the aforementioned structures, all of this air, together with any debris it is carrying, must pass through the radiator. As a result, the practical limitation on the density of radiator fins is about 3 to 4 fins per centimeter (8 to 10 fins per inch). Any more than this, and the radiator quickly becomes clogged with debris.
U.S. Pat. Nos. 4,401,154 (Anders et al.) and 4,542,786 (Anders) elaborate on the particulars of the core elements of the Bentz structure. In the Anders references, a slight gap is provided at the rear apex of adjacent core elements, so that air can flow between the core elements rather than through the core elements. Adjacent core elements are not sharply angled relative to one another, so that the general air flow impinges on the face of each core element, causing some degree of turbulence. Indeed, the second Anders patent is an attempt to reposition coolant tubes through the core elements in an attempt to reduce this turbulance.
The slight spacing provided in the Anders references allows some debris to pass the radiator without going through the core elements. This in turn means that the radiator fins can be packed more closely together. Although this is not mentioned in the patents, the commercial embodiments have fin densities on the order of 13-14 fins per centimeter (33-35 fins per inch). The Anders structures have the disadvantage that the number of core elements and their positioning creates a high degree of complexity and turbulence. In addition, providing gaps between each of half a dozen core elements means that a substantial volume of air is passing through the gaps, where it has no cooling effect. Finally, once through the radiator, the debris-laden air is blown back on the engine where the debris may be deposited.